The evidence obtained in prior years from this project suggests that prostaglandins are likely candidates for mediators of at least some of the actions of cannabinoids. The primary goal of the present proposal is to further pursue this hypothesis with emphasis on the psychotropic actions of Delta1-THC. An additional goal is to show that the effects of cannabionoids on arachidonic acid metabolism in cell culture systems is a useful model for studying the underlying molecular events involved in cannabinoid action. Thus, this project is part of the overall effort in our laboratory which is to study the mechanism of action of cannabinoids. Experiments will be done to further describe the effects of cannabinoids on prostaglandin synthesis both in vivo in mice and in vitro using a variety of cell lines. Structure-activity profiles will be obtained and phenomena such as tolerance and drug interactions will be studied in these model systems. These experiments will be designed to complement our more general interest in the biochemical events surrounding cannabinoid actions.